Add support for using AMD modules from extensions modules.

extensions/renderer/module_system.h

Index: extensions/renderer/module_system.h
diff --git a/extensions/renderer/module_system.h b/extensions/renderer/module_system.h
index eec25cce5228a510eff77d9b3c6c2ec98497f535..4ab628fe0ea6c3962b23fffb709fb9d94aad2f87 100644
--- a/extensions/renderer/module_system.h
+++ b/extensions/renderer/module_system.h
@@ -15,6 +15,7 @@
 #include "base/memory/scoped_ptr.h"
 #include "extensions/renderer/native_handler.h"
 #include "extensions/renderer/object_backed_native_handler.h"
+#include "gin/modules/module_registry_observer.h"
 #include "v8/include/v8.h"
 
 namespace extensions {
@@ -37,7 +38,8 @@ class ScriptContext;
 // Note that a ModuleSystem must be used only in conjunction with a single
 // v8::Context.
 // TODO(koz): Rename this to JavaScriptModuleSystem.
-class ModuleSystem : public ObjectBackedNativeHandler {
+class ModuleSystem : public ObjectBackedNativeHandler,
+                     public gin::ModuleRegistryObserver {
  public:
   class SourceMap {
    public:
@@ -158,9 +160,6 @@ class ModuleSystem : public ObjectBackedNativeHandler {
   // Called when an exception is thrown but not caught.
   void HandleException(const v8::TryCatch& try_catch);
 
-  // Ensure that require_ has been evaluated from require.js.
-  void EnsureRequireLoaded();
-
   void RequireForJs(const v8::FunctionCallbackInfo<v8::Value>& args);
   v8::Local<v8::Value> RequireForJsInner(v8::Handle<v8::String> module_name);
 
@@ -183,15 +182,29 @@ class ModuleSystem : public ObjectBackedNativeHandler {
   v8::Handle<v8::Value> RequireNativeFromString(const std::string& native_name);
   void RequireNative(const v8::FunctionCallbackInfo<v8::Value>& args);
 
-  // Wraps |source| in a (function(require, requireNative, exports) {...}).
+  // Return a promise for a requested module.
+  // |args[0]| - the name of a module.
+  void RequireAsync(const v8::FunctionCallbackInfo<v8::Value>& args);
+
+  // Wraps |source| in a (function(define, require, requireNative, ...) {...}).
   v8::Handle<v8::String> WrapSource(v8::Handle<v8::String> source);
 
   // NativeHandler implementation which returns the private area of an Object.
   void Private(const v8::FunctionCallbackInfo<v8::Value>& args);
 
-  // NativeHandler implementation which returns a function wrapper for a
-  // provided function.
-  void CreateFunctionWrapper(const v8::FunctionCallbackInfo<v8::Value>& args);
+  // Loads and runs a Javascript module.
+  v8::Handle<v8::Value> LoadModule(const std::string& module_name);
+
+  // Invoked when a module is loaded in response to a requireAsync call.
+  // Resolves |resolver| with |value|.
+  void OnModuleLoaded(
+      scoped_ptr<v8::UniquePersistent<v8::Promise::Resolver> > resolver,
+      v8::Handle<v8::Value> value);
+
+  // gin::ModuleRegistryObserver overrides.
+  virtual void OnDidAddPendingModule(
+      const std::string& id,
+      const std::vector<std::string>& dependencies) OVERRIDE;
 
   ScriptContext* context_;
 
@@ -212,6 +225,8 @@ class ModuleSystem : public ObjectBackedNativeHandler {
 
   std::set<std::string> overridden_native_handlers_;
 
+  base::WeakPtrFactory<ModuleSystem> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(ModuleSystem);
 };